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Background: Disease‐specific therapy aims to improve symptoms, stabilise current disease and delay progression in patients with Fabry disease. In Australia, treatment access is subject to eligibility criteria initially established in 2004. Patients and their clinicians question why these criteria have remained unchanged despite significant progress in disease understanding. Aims: Appraise the clinical quality of the Australian treatment access criteria. Methods: The Fabry Australia Medical Advisory Committee (N = 6) used the Appraisal of Guidelines for REsearch and Evaluation Global Rating Scale (AGREE II GRS) to assess the clinical quality of the current treatment eligibility criteria. They reviewed the literature, developed 17 clinical statements to help guide reforms of the eligibility criteria and achieved consensus (achievement of ≥75% agreement in the range 5–7 on a 7‐point Likert scale) through anonymous voting. The findings were applied to develop proposals for revised classification and treatment initiation criteria. Results: The current treatment eligibility criteria underperformed on the AGREE II GRS. They are pragmatic but out‐of‐step with contemporary data. Consensus was achieved on all 17 proposed clinical statements. There was strong agreement to differentiate classical male Fabry patients to facilitate timelier access to Fabry‐specific treatment. There was also agreement on the value of adopting relevant organ involvement criteria in classical female patients and patients with non‐classical disease. Conclusions: Australian access criteria are misaligned with current clinical evidence. The clinical statements and proposed classification and initiation criteria should prompt discussions to support more equitable access to treatment and better align Australian practice with contemporary evidence and international guidelines. [ABSTRACT FROM AUTHOR]

Lysosomal enzyme deficiency in mucopolysaccharidosis (MPS) I results in glycosaminoglycan (GAG) accumulation leading to pain and limited physical function. Disease‐modifying treatments for MPS I, enzyme replacement, and hematopoietic stem cell therapy (HSCT), do not completely resolve MPS I symptoms, particularly skeletal manifestations. The GAG reduction, anti‐inflammatory, analgesic, and tissue remodeling properties of pentosan polysulfate sodium (PPS) may provide disease‐modifying treatment for musculoskeletal symptoms and joint inflammation in MPS I following ERT and/or HSCT. The safety and efficacy of PPS were evaluated in four subjects with MPS I aged 14–19 years, previously treated with ERT and/or HSCT. Subjects received doses of 0.75 mg/kg or 1.5 mg/kg PPS via subcutaneous injections weekly for 12 weeks, then every 2 weeks for up to 72 weeks. PPS was well tolerated at both doses with no serious adverse events. MPS I GAG fragment (UA‐HNAc [1S]) levels decreased at 73 weeks. Cartilage degradation biomarkers serum C‐telopeptide of crosslinked collagen (CTX) type I (CTX‐I) and type II (CTX‐II) and urine CTX‐II decreased in all subjects through 73 weeks. PROMIS scores for pain interference, pain behavior, and fatigue decreased in all subjects through 73 weeks. Physical function, measured by walking distance and dominant hand function, improved at 49 and 73 weeks. Decreased GAG fragments and cartilage degradation biomarkers, and positive PROMIS outcomes support continued study of PPS as a potential disease‐modifying treatment for MPS I with improved pain and function outcomes. [ABSTRACT FROM AUTHOR]

3-Hydroxy-3-Methylglutaryl-CoA Lyase (HMGCL) deficiency can be a very severe disorder that typically presents with acute metabolic decompensation with features of hypoketotic hypoglycemia, hyperammonemia, and metabolic acidosis. A retrospective chart and literature review of Australian patients over their lifespan, incorporating acute and long-term dietary management, was performed. Data from 10 patients contributed to this study. The index case of this disorder was lost to follow-up, but there is 100% survival in the remainder of the cases despite several having experienced life-threatening episodes. In the acute setting, five of nine patients have used 900 mg/kg/day of sodium D,L 3-hydroxybutyrate in combination with intravenous dextrose-containing fluids (delivering glucose above estimated basal utilization requirements). All patients have been on long-term protein restriction, and those diagnosed more recently have had additional fat restriction. Most patients take L-carnitine. Three children and none of the adults take nocturnal uncooked cornstarch. Of the cohort, there were two patients that presented atypically—one with fulminant liver failure and the other with isolated developmental delay. Dietary management in patients with HMGCL deficiency is well tolerated, and rapid institution of acute supportive metabolic treatment is imperative to optimizing survival and improve outcomes in this disorder. [ABSTRACT FROM AUTHOR]

This document provides consensus‐based recommendations for general physicians and primary care physicians who diagnose and manage patients with mitochondrial diseases (MD). It builds on previous international guidelines, with particular emphasis on clinical management in the Australian setting. This statement was prepared by a working group of medical practitioners, nurses and allied health professionals with clinical expertise and experience in managing Australian patients with MD. As new treatments and management plans emerge, these consensus‐based recommendations will continue to evolve, but current standards of care are summarised in this document. [ABSTRACT FROM AUTHOR]

Mutations in either the mitochondrial or nuclear genomes are associated with a diverse group of human disorders characterized by impaired mitochondrial respiration. Within this group, an increasing number of mutations have been identified in nuclear genes involved in mitochondrial RNA metabolism, including ELAC2. The ELAC2 gene codes for the mitochondrial RNase Z, responsible for endonucleolytic cleavage of the 3′ ends of mitochondrial pre‐tRNAs. Here, we report the identification of 16 novel ELAC2 variants in individuals presenting with mitochondrial respiratory chain deficiency, hypertrophic cardiomyopathy (HCM), and lactic acidosis. We provide evidence for the pathogenicity of the novel missense variants by studying the RNase Z activity in an in vitro system. We also modeled the residues affected by a missense mutation in solved RNase Z structures, providing insight into enzyme structure and function. Finally, we show that primary fibroblasts from the affected individuals have elevated levels of unprocessed mitochondrial RNA precursors. Our study thus broadly confirms the correlation of ELAC2 variants with severe infantile‐onset forms of HCM and mitochondrial respiratory chain dysfunction. One rare missense variant associated with the occurrence of prostate cancer (p.Arg781His) impairs the mitochondrial RNase Z activity of ELAC2, suggesting a functional link between tumorigenesis and mitochondrial RNA metabolism [ABSTRACT FROM AUTHOR]

Background: Late-onset Pompe disease is a rare genetic neuromuscular disorder caused by lysosomal acid alpha-glucosidase (GAA) deficiency that ultimately results in mobility loss and respiratory failure. Current enzyme replacement therapy with recombinant human (rh)GAA has demonstrated efficacy in subjects with late-onset Pompe disease. However, long-term effects of rhGAA on pulmonary function have not been observed, likely related to inefficient delivery of rhGAA to skeletal muscle lysosomes and associated deficits in the central nervous system. To address this limitation, reveglucosidase alfa, a novel insulin-like growth factor 2 (IGF2)-tagged GAA analogue with improved lysosomal uptake, was developed. This study evaluated the pharmacokinetics, safety, and exploratory efficacy of reveglucosidase alfa in 22 subjects with late-onset Pompe disease who were previously untreated with rhGAA.Results: Reveglucosidase alfa plasma concentrations increased linearly with dose, and the elimination half-life was <1.2 h. Eighteen of 22 subjects completed 72 weeks of treatment. The most common adverse events were hypoglycemia (63%), dizziness, fall, headache, and nausea (55% for each). Serious adverse events included hypersensitivity (n = 1), symptomatic hypoglycemia (n = 2), presyncope (n = 1), and acute cardiac failure (n = 1). In the dose-escalation study, all treated subjects tested positive for anti-reveglucosidase alfa, anti-rhGAA, anti-IGF1, and anti-IGF2 antibodies at least once. Subjects receiving 20 mg/kg of reveglucosidase alfa demonstrated increases in predicted maximum inspiratory pressure (13.9%), predicted maximum expiratory pressure (8.0%), forced vital capacity (-0.4%), maximum voluntary ventilation (7.4 L/min), and mean absolute walking distance (22.3 m on the 6-min walk test) at 72 weeks.Conclusions: Additional studies are needed to further assess the safety and efficacy of this approach. Improvements in respiratory muscle strength, lung function, and walking endurance in subjects with LOPD may make up for the risk of hypersensitivity reactions and hypoglycemia. Reveglucosidase alfa may provide a new treatment option for patients with late-onset Pompe disease.Trial Registration: ISRCTN01435772 and ISRCTN01230801 , registered 27 October 2011. [ABSTRACT FROM AUTHOR]

Introduction: Fabry disease is a rare, inherited X-linked lysosomal storage disease characterized by a wide spectrum of heterogeneously progressive clinical phenotypes, and which results in progressive kidney disease, cardiomyopathy, cerebrovascular disease, and reduced life expectancy. Disease-specific therapy aims to improve symptoms, stabilize current disease and delay progression. In Australia treatment access requires that patients meet pre-specified criteria, which have been in place for more than 15 years. Patient questions prompted the patient organization, Fabry Australia, to investigate why these criteria had remained unchanged despite significant progress in the understanding and management of Fabry disease. Methods: A panel comprising two members of Fabry Australia and its Medical Advisory Committee conducted a review of the literature. The aim of this was to inform the clinical quality of the Australian treatment access criteria with reference to international guidelines and contemporary data. The findings from the literature were applied to develop consensus recommendations for classification and Fabry-specific treatment initiation criteria in diagnosed patients. Results: Evidence supports earlier treatment with reduced barriers to access in some circumstances. Australian access criteria are misaligned with this. They do not distinguish between classical and non-classical Fabry phenotypes, neglect the impact of quality of life and gastrointestinal symptoms, and impose symptom-severity related criteria, which may lead to unnecessary treatment initiation delay. An updated framework is presented. It differentiates phenotypes, facilitates more timely access to Fabry-specific treatment for classical males, and supports relevant organ involvement criteria in classical females and patients with non-classical disease. Conclusions: A well-performing health technology assessment system facilitates patient access to cost-effective treatments that improve health outcomes. Timely treatment initiation is important to avoid irreversible organ damage in Fabry patients. Patients' questions about out-dated access criteria has prompted research and uncovered barriers that are no longer clinically valid. The perspectives of the patient as a stakeholder in their disease management should not be overlooked when assessing the value of health technologies in the rare disease setting. [ABSTRACT FROM AUTHOR]

The article describes the case of a preterm infant with long-chain 3-hydroxyacyl-coenzyme A dehydrogenase (LCHAD) deficiency diagnosed on neonatal screening test (NST), in which the fatty acid profiles were measured over time after birth. The infant was delivered by cesarean section at 29 weeks' gestational age due to fulminant hypertension, elevated liver enzymes, and low platelets (HELLP) syndrome in the mother.

Mitochondrial protein synthesis requires charging a mitochondrial tRNA with its amino acid. Here, the authors describe pathogenic variants in the GatCAB protein complex genes required for the generation of glutaminyl-mt-tRNAGln, that impairs mitochondrial translation and presents with cardiomyopathy. Mitochondrial protein synthesis requires charging mt-tRNAs with their cognate amino acids by mitochondrial aminoacyl-tRNA synthetases, with the exception of glutaminyl mt-tRNA (mt-tRNAGln). mt-tRNAGln is indirectly charged by a transamidation reaction involving the GatCAB aminoacyl-tRNA amidotransferase complex. Defects involving the mitochondrial protein synthesis machinery cause a broad spectrum of disorders, with often fatal outcome. Here, we describe nine patients from five families with genetic defects in a GatCAB complex subunit, including QRSL1, GATB, and GATC, each showing a lethal metabolic cardiomyopathy syndrome. Functional studies reveal combined respiratory chain enzyme deficiencies and mitochondrial dysfunction. Aminoacylation of mt-tRNAGln and mitochondrial protein translation are deficient in patients’ fibroblasts cultured in the absence of glutamine but restore in high glutamine. Lentiviral rescue experiments and modeling in S. cerevisiae homologs confirm pathogenicity. Our study completes a decade of investigations on mitochondrial aminoacylation disorders, starting with DARS2 and ending with the GatCAB complex. [ABSTRACT FROM AUTHOR]

Two-thirds of patients with mucopolysaccharidosis II (MPS II; Hunter syndrome) have cognitive impairment. This phase 2/3, randomized, controlled, open-label, multicenter study (NCT02055118) investigated the effects of intrathecally administered idursulfase-IT on cognitive function in patients with MPS II. Children older than 3 years with MPS II and mild-to-moderate cognitive impairment (assessed by Differential Ability Scales-II [DAS-II], General Conceptual Ability [GCA] score) who had tolerated intravenous idursulfase for at least 4 months were randomly assigned (2:1) to monthly idursulfase-IT 10 mg (n = 34) via an intrathecal drug delivery device (IDDD; or by lumbar puncture) or no idursulfase-IT treatment (n = 15) for 52 weeks. All patients continued to receive weekly intravenous idursulfase 0.5 mg/kg as standard of care. Of 49 randomized patients, 47 completed the study (two patients receiving idursulfase-IT discontinued). The primary endpoint (change from baseline in DAS-II GCA score at week 52 in a linear mixed-effects model for repeated measures analysis) was not met: although there was a smaller decrease in DAS-II GCA scores with idursulfase-IT than with no idursulfase-IT at week 52, this was not significant (least-squares mean treatment difference [95% confidence interval], 3.0 [−7.3, 13.3]; p = 0.5669). Changes from baseline in Vineland Adaptive Behavioral Scales-II Adaptive Behavior Composite scores at week 52 (key secondary endpoint) were similar in the idursulfase-IT (n = 31) and no idursulfase-IT (n = 14) groups. There were trends towards a potential positive effect of idursulfase-IT across DAS-II composite, cluster, and subtest scores, notably in patients younger than 6 years at baseline. In a post hoc analysis, there was a significant (p = 0.0174), clinically meaningful difference in change from baseline in DAS-II GCA scores at week 52 with idursulfase-IT (n = 13) versus no idursulfase-IT (n = 6) among those younger than 6 years with missense iduronate-2-sulfatase gene variants. Overall, idursulfase-IT reduced cerebrospinal glycosaminoglycan levels from baseline by 72.0% at week 52. Idursulfase-IT was generally well tolerated. These data suggest potential benefits of idursulfase-IT in the treatment of cognitive impairment in some patients with neuronopathic MPS II. After many years of extensive review and regulatory discussions, the data were found to be insufficient to meet the evidentiary standard to support regulatory filings. • Trends towards cognitive benefits with intrathecal idursulfase for some patients. • Significant effects in those <6 years with missense iduronate-2-sulfatase variants • After 52 weeks, cerebrospinal glycosaminoglycan levels decreased by 72%. • Most adverse events were mild or moderate; none led to discontinuation. • Overall, the data did not meet evidentiary standards for regulatory filing. [ABSTRACT FROM AUTHOR]

Enzyme replacement therapy with weekly infused intravenous (IV) idursulfase is effective in treating somatic symptoms of mucopolysaccharidosis II (MPS II; Hunter syndrome). A formulation of idursulfase for intrathecal administration (idursulfase-IT) is under investigation for the treatment of neuronopathic MPS II. Here, we report 36-month data from the open-label extension (NCT02412787) of a phase 2/3, randomized, controlled study (HGT-HIT-094; NCT02055118) that assessed the safety and efficacy of monthly idursulfase-IT 10 mg in addition to weekly IV idursulfase on cognitive function in children older than 3 years with MPS II and mild-to-moderate cognitive impairment. Participants were also enrolled in this extension from a linked non-randomized sub-study of children younger than 3 years at the start of idursulfase-IT therapy. The extension safety population comprised 56 patients who received idursulfase-IT 10 mg once a month (or age-adjusted dose for sub-study patients) plus IV idursulfase (0.5 mg/kg) once a week. Idursulfase-IT was generally well tolerated over the cumulative treatment period of up to 36 months. Overall, 25.0% of patients had at least one adverse event (AE) related to idursulfase-IT; most treatment-emergent AEs were mild in severity. Of serious AEs (reported by 76.8% patients), none were considered related to idursulfase-IT treatment. There were no deaths or discontinuations owing to AEs. Secondary efficacy analyses (in patients younger than 6 years at phase 2/3 study baseline; n = 40) indicated a trend for improved Differential Ability Scale-II (DAS-II) General Conceptual Ability (GCA) scores in the early idursulfase-IT versus delayed idursulfase-IT group (treatment difference over 36 months from phase 2/3 study baseline: least-squares mean, 6.8 [90% confidence interval: −2.1, 15.8; p = 0.2064]). Post hoc analyses of DAS-II GCA scores by genotype revealed a clinically meaningful treatment effect in patients younger than 6 years with missense variants of the iduronate-2-sulfatase gene (IDS) (least-squares mean [standard error] treatment difference over 36 months, 12.3 [7.24]). These long-term data further suggest the benefits of idursulfase-IT in the treatment of neurocognitive dysfunction in some patients with MPS II. After many years of extensive review and regulatory discussions, the data were found to be insufficient to meet the evidentiary standard to support regulatory filings. • Intrathecal idursulfase was generally well tolerated over 3 years. • Most adverse effects were mild; none led to death or discontinuation. • Efficacy analyses in young patients suggest benefits of early treatment initiation. • Clinically meaningful benefit in patients under 6 years old with missense variants. • Overall, the data did not meet evidentiary standards for regulatory filing. [ABSTRACT FROM AUTHOR]

Several studies have shown serum fibroblast growth factor 21 (FGF21) and growth differentiation factor 15 (GDF15) levels are elevated in patients with mitochondrial disease (MD) where myopathy is a feature. In this study we investigated the utility of FGF21 and GDF15 as biomarkers for MD in a phenotypically and genotypically diverse pediatric cohort with suspected MD against a panel of healthy controls and non-mitochondrial disease controls with some overlapping clinical features. Serum was collected from 56 children with MD, 104 children with non-mitochondrial disease (27 neuromuscular, 26 cardiac, 21 hepatic, 30 renal) and 30 pediatric controls. Serum FGF21 and GDF15 concentrations were measured using ELISA, and their ability to detect MD was determined. Median FGF21 and GDF15 serum concentrations were elevated 17-fold and 3-fold respectively in pediatric MD patients compared to the healthy control group. Non-mitochondrial disease controls had elevated serum GDF15 concentrations while FGF21 concentrations were in the normal range. Elevation of GDF15 in a range of non-mitochondrial pediatric disorders limits its use as a MD biomarker. FGF21 was elevated in MD patients with a spectrum of clinical phenotypes, including those without myopathy. Serum FGF21 had an area under the receiver operating characteristic curve of 0.87, indicating good ability to discriminate between pediatric MD and healthy and non-mitochondrial disease controls. Triaging of pediatric MD patients by clinical phenotyping and serum FGF21 testing, followed by massively parallel sequencing, may enable more rapid diagnosis of pediatric MD. • Serum FGF21 and GDF15 were elevated in a range of pediatric mitochondrial diseases. • Serum GDF15 was elevated in non-mitochondrial pediatric disease cohorts. • Serum FGF21 was not elevated in non-mitochondrial pediatric disease cohorts. • Serum FGF21 was elevated in both mitochondrial myopathy and neuronal phenotypes. • Serum FGF21 was a good biomarker of pediatric mitochondrial disease. [ABSTRACT FROM AUTHOR]

Background: Pompe disease is a rare disorder characterised by progressive loss of muscle and respiratory function due to acid α-glucosidase deficiency. Enzyme replacement therapy with recombinant human acid α-glucosidase, alglucosidase alfa, is the first approved treatment for the disease, but some patients do not respond, and many do not show a sustained benefit. We aimed to assess the safety and efficacy of an investigational two-component therapy (cipaglucosidase alfa, a novel recombinant human acid α-glucosidase, plus miglustat, an enzyme stabiliser) for late-onset Pompe disease.Methods: We did a randomised, double-blind, parallel-group, phase 3 trial at 62 neuromuscular and metabolic medical centres in 24 countries in the Americas, Asia-Pacific, and Europe. Eligible participants were aged 18 years or older with late-onset Pompe disease, and had either been receiving alglucosidase alfa for at least 2 years or were enzyme replacement therapy-naive. Participants were randomly assigned (2:1) using interactive response technology software, stratified by 6-min walk distance and previous enzyme replacement therapy status, to intravenous cipaglucosidase alfa (20 mg/kg) plus oral miglustat or to intravenous alglucosidase alfa (20 mg/kg) plus oral placebo once every 2 weeks for 52 weeks. Patients, investigators, and outcome assessors were masked to treatment assignment. The primary endpoint was change from baseline to week 52 in 6-min walk distance, assessed using a mixed-effect model for repeated measures analysis for comparison of superiority in the intention-to-treat population (all patients who received at least one dose of study drug). This study is now complete and is registered with ClinicalTrials.gov, NCT03729362.Findings: Between Dec 3, 2018, and Nov 26, 2019, 130 patients were screened for eligibility and 125 were enrolled and randomly assigned to receive cipaglucosidase alfa plus miglustat (n=85) or alglucosidase alfa plus placebo (n=40). Two patients in the alglucosidase alfa plus placebo group did not receive any dose due to absence of genotype confirmation of late-onset Pompe disease and were excluded from analysis. Six patients discontinued (one in the alglucosidase alfa plus placebo group, five in the cipaglucosidase alfa plus miglustat group), and 117 completed the study. At week 52, mean change from baseline in 6-min walk distance was 20·8 m (SE 4·6) in the cipaglucosidase alfa plus miglustat group versus 7·2 m (6·6) in the alglucosidase alfa plus placebo group using last observation carried forward (between-group difference 13·6 m [95% CI -2·8 to 29·9]). 118 (96%) of 123 patients experienced at least one treatment-emergent adverse event during the study; the incidence was similar between the cipaglucosidase alfa plus miglustat group (n=81 [95%]) and the alglucosidase alfa plus placebo group (n=37 [97%]). The most frequently reported treatment-emergent adverse events were fall (25 [29%] patients in the cipaglucosidase alfa plus miglustat group vs 15 [39%] in the alglucosidase alfa plus placebo group), headache (20 [24%] vs 9 [24%]), nasopharyngitis (19 [22%] vs 3 [8%]), myalgia (14 [16%] vs 5 [13%]), and arthralgia (13 [15%]) vs 5 [13%]). 12 serious adverse events occurred in eight patients in the cipaglucosidase alfa plus miglustat group; only one event (anaphylaxis) was deemed related to study drug. One serious adverse event (stroke) occurred in the alglucosidase alfa plus placebo group, which was deemed unrelated to study drug. There were no deaths.Interpretation: Cipaglucosidase alfa plus miglustat did not achieve statistical superiority to alglucosidase alfa plus placebo for improving 6-min walk distance in our overall population of patients with late-onset Pompe disease. Further studies should investigate the longer-term safety and efficacy of cipaglucosidase alfa plus miglustat and whether this investigational two-component therapy might provide benefits, particularly in respiratory function and in patients who have been receiving enzyme replacement therapy for more than 2 years, as suggested by our secondary and subgroup analyses.Funding: Amicus Therapeutics. [ABSTRACT FROM AUTHOR]

Late-onset Pompe disease (LOPD) is a rare lysosomal storage disorder characterized by progressive loss of muscle and respiratory function resulting from acid α-glucosidase (GAA) deficiency, for which recombinant human GAA enzyme replacement therapy (rhGAA ERT: alglucosidase alfa) is currently available. Here, we report the 12-month interim results from ATB200-02 (NCT02675465), a first-in-human, open-label, phase 1/2 trial evaluating a next-generation rhGAA/chaperone regimen AT-GAA (ATB200/AT2221) in adults with LOPD. The study enrolled 20 patients in 3 cohorts: ERT-switch ambulatory (n=11), ERT-switch nonambulatory (n=4), and ERT-naive ambulatory (n=5). 6-minute walk test (meters) improved in ambulatory ERT-switch patients (n=10 mean change [SD]: month 6, 23.9 [52.2] month 9, 24.5 [40.8] month 12, 42.2 [46.5]) and ERT-naive patients (n=5 month 6, 41.8 [29.4] month 9, 63.5 [23.1] month 12, 63.1 [29.1]). Other motor function tests were generally consistent with these results. Nonambulatory ERT-switch patients demonstrated increases in upper extremity strength at months 6, 9, and 12 as assessed by quantitative and manual muscle testing. Forced vital capacity (% predicted) increased in ERT-naive patients (n=5, mean change: month 6, 4.2 month 9, 6.2 month 12, 4.4), and was generally stable in ambulatory ERT-switch patients (n=9, month 6, -1.3 month 9, -1.7 month 12, -3.3). AT-GAA (ATB200/AT2221) was associated with reductions in creatine kinase and urine hexose tetrasaccharide. The most common treatment-emergent adverse events were upper and lower abdominal pain, diarrhea, and nasopharyngitis. Three events of infusion-associated reactions (skin discoloration, erythema, pruritus) occurred in ≥550 infusions. Data from this interim analysis show clinical benefits of AT-GAA (ATB200/AT2221) in ERT-naive patients and both ambulatory and nonambulatory ERT-experienced patients, suggesting that ATB200/AT2221 can be an effective and well-tolerated treatment for adults with LOPD. Updated 24-month efficacy/safety data will be included in the presentation. [ABSTRACT FROM AUTHOR]

In glucose transporter 1 deficiency syndrome (Glut1DS), cerebrospinal fluid glucose (CSFG) and CSFG to blood glucose ratio (CBGR) show significant differences among groups classified by phenotype or genotype. The purpose of this study was to investigate the association between these biochemical parameters and Glut1DS severity. The medical records of 45 patients who visited Osaka University Hospital between March 2004 and December 2021 were retrospectively examined. Neurological status was determined using the developmental quotient (DQ), assessed using the Kyoto Scale of Psychological Development 2001, and the Scale for the Assessment and Rating of Ataxia (SARA). CSF parameters included CSFG, CBGR, and CSF lactate (CSFL). CSF was collected from 41 patients, and DQ and SARA were assessed in 24 and 27 patients, respectively. Simple regression analysis showed moderate associations between neurological status and biochemical parameters. CSFG resulted in a higher R2 than CBGR in these analyses. CSF parameters acquired during the first year of life were not comparable to those acquired later. CSFL was measured in 16 patients (DQ and SARA in 11 and 14 patients, respectively). Although simple regression analysis also showed moderate associations between neurological status and CSFG and CSFL, the multiple regression analysis for DQ and SARA resulted in strong associations through the use of a combination of CSFG and CSFL as explanatory variables. The severity of Glut1DS can be predicted from CSF parameters. Glucose and lactate are independent contributors to the developmental and neurological status in Glut1DS. [Display omitted] • Glucose transporter 1 deficiency syndrome severity is predictable. • Cerebrospinal fluid glucose correlates with the severity. • Cerebrospinal fluid lactate is another predictor of severity. • Parameters for prediction differ between older children and those <1 year of age. • Innate severity should be considered while evaluating ketogenic diet efficacy. [ABSTRACT FROM AUTHOR]